Disagree.
Every ecommerce company and retailer looks at payment fees as money left on the table.
The more money Stripe take on, the more they need to return to investors, and so the more pressure to make margin. That is the opportunity for the future.
I too doubt it would come from a bank, nor from Visa and Mastercard... but could another exist? Yes!
If it came from a big player, I'd be looking at Shopify.